Hydrogen sulfide and mercaptans are present in underground water removed with crude oil, in crude oil itself, in natural gases and in gases associated with underground water and crude oil. Hydrogen sulfide and mercaptans are characterized by highly noxious odors and typically are highly corrosive. Uncontrolled emissions of hydrogen sulfide give rise to severe health hazards. The presence of hydrogen sulfide and mercaptans is further objectionable because they often react with desirable hydrocarbons as well as fuel system components.